The Disappearance of the Vultures

In 1989, India was over-run by rotting flesh, plagues of flies, and rabid dogs – all because they lost some birds. As many as 44 million vultures, 99 percent of several species, had disappeared across Asia almost overnight — and no one knew why. It was a complete mystery.

Historical vulture populationsGoutam Narayan/RSPB

India used to have very large vulture populations and it is important to understand why and how this fits with Indian culture. Vultures are birds of prey that live in communities and human environments and are very dependent on human activities. 80 percent of the Indian population is Hindu, and as a culture, Hinduism is particularly favorable to vultures.

Hindus do not eat cows, which they consider sacred. Cows are used, however, for milk products and as beasts of burden. When a cow dies, it is not eaten by humans, but by vultures. Of the estimated 500 million head of cattle in India, only 4 percent are destined for consumption by humans as meat.

Vultures are therefore India's optimal natural animal disposal system, processing carcasses even in cities. Up to 15,000 vultures have been observed at the carcass depositories of New Delhi. In the 1990s, scientists and naturalists began noticing a decrease in the number of vultures in the skies over India. As this decline accelerated, they and others in the international scientific community looked to find the reason.

The loss of these birds had several unexpected results:

As carcasses once eaten by vultures now rotted in village fields, drinking water became seriously contaminated.

The disappearance of vultures has allowed other species, such as rats and wild dogs, to take their place. These newly abundant scavengers, however, are not as efficient as vultures. While a vulture's metabolism is in fact a true "dead-end" for pathogens, dogs and rats instead become carriers of the pathogens and therefore spread diseases throughout human populations such as rabies, anthrax and plague.

Today in India, 30,000 people die from rabies each year, more than half the world's total. A person is bitten every 2 seconds, and one dies from rabies every 30 minutes. India today has an estimated 18 million wild dogs, the largest population of carnivores in the world.

Vulture landing on its handlerPassion Planet

Vulture Facts

Most species of vulture have featherless heads and necks so they can get in and out of a carcass without getting feathers caught on bones and soaked in blood.

Being scavengers, they are never sure where their next meal will come from so they are capable of gorging on 20% of their body weight in one meal.

An Egyptian Vulture close up
They are equipped with a digestive system that contains special acids that will dissolve anthrax, botulism and cholera bacteria.

They are smart too; one of the few animals to use tools, Egyptian vultures use rocks to break open ostrich eggs.

Vultures associated with scavenging, death and disease are getting a new press as highly efficient environmental cleaners and experts at flight.

Vultures do not have a good sense of smell – they rely on incredible eyesight to locate food. A soaring vulture can spot a 3-foot animal carcass from 4 miles away.

Some species have been known to soar for 6 hours without flapping.

The Rueppell’s griffon vulture is reportedly the world’s highest flying bird. In 1973, one collided with an airplane off the Ivory Coast; at the time, the plane was flying at 37,000 feet.

The Vulture Detectives

The Vulture Detectives

In the mid-90s Scientist Vibhu Prakash from the Bombay Natural History Society (BNHS) on one his visits to the national parks in northern India, realized the vultures were not just in decline – they were gone. Vibhu got on the phone to colleagues across India and they were seeing the same thing. Pakistan and Nepal also saw huge declines. By 2007 some species had decline by 99.9 percent of their former numbers, hundreds of thousands of birds had died and no one had a clue why. They may not have known why the birds had gone but the consequences were becoming clear — the result was a plague of rotting flesh, an increase in disease and thousands more rabid dogs. In India, cows and buffalos are not considered food, and when they die, carcasses are dumped at ‘carcass dumps’ across India. Before the crash huge numbers of vultures would strip the carcasses bare in a matter of minutes, but without them, the dead meat piled high in rotting masses fed on only by a plague of stray dogs, fuelling a rabies epidemic.

For years Vibhu and colleagues across Asia, working with other experts from Europe and the U.S. searched for an answer. Eventually researchers in Pakistan conclusively proved that a veterinary painkiller used in cows and buffalo across Asia was lethal in the smallest of doses to any species of Gyps vultures. A campaign began in earnest to try and stop the use of the drug. Eventually the Indian government banned the use of diclofenac for animals but it is still used for humans, so while decline of some populations has slowed there is still poison in the system. There were alternatives to diclofenac, but it was the cheapest option so farmers keen to keep their buffalos working longer still turned to the drug, buying it on the black market. An unexpected ally was found in the pharmaceutical company that produced an alternative drug; they agreed to produce the drug and sell it at cost price making it at last a viable option.